The present invention relates in general to transformer testing and, more particularly, to automated test equipment for transformer testing.
Transformers are tested by their manufacturers and by electric utilities. The tests may include polarity, phase relation, core loss, load loss, and transformer ratio. However, there is no universal testing procedure followed by all testers. Different standards are followed and sometimes transformer manufacturers implement their own custom test sequences. Many times, the customer requires the manufacturer to follow a certain test sequence, and with many different customers, changing test sequences after every order is not an easy task for the manufacturer""s transformer testing facility. Moreover, different systems are typically needed to implement different tests.
Automated testers test transformers according to a test program having a predetermined sequence of test instructions. In other words, the test program executes a fixed sequence of test instructions that cannot be edited or is extremely difficult to edit. For example, if the test program selects a transformer test which is programmed to first run a winding resistance test and then a voltage ratio test at a certain set of parameters, then each time the transformer test is selected, the winding resistance test is performed first and the voltage ratio test is performed second. Thus, the sequence of test instructions is arranged such that a sequence of test instructions specifying a winding resistance test is listed before a sequence of test instructions specifying a voltage ratio test. The disadvantage of having a test program with a fixed sequence of test instructions is that the user does not have the flexibility of editing or creating a particular sequence to optimize the transformer test program.
Therefore, an automated transformer tester having a sequence editor to edit or to create customized test programs, along with a test engine that can implement a variety of tests and test sequences, is desirable. It is further desirable to have one testing system that can perform multiple tests without the need for different controllers or systems.
The present invention is directed to a transformer test sequence editor for transformer testing that enables a tester to implement any test sequence, whether standard or customized, with any test parameters. A transformer test sequence engine is also provided that enables a tester to perform tests created using a test sequence editor and to monitor the test results. The automated test sequence editor and engine allows the transformer tester to edit a test sequence in any order. The tester can also modify any or all of the test parameters.
According to an embodiment of the invention, a system for testing a transformer comprises a processor comprising a transformer test engine adapted to execute a transformer test sequence; a controller coupled to the processor to output control commands; a switcher coupled between the controller and the transformer to switch power to the controller responsive to the control commands; and a metering system coupled between the transformer and the processor to receive measurements from the transformer and provide the measurements to the processor.
According to aspects of the invention, a memory device is coupled to the processor for storing transformer specifications. A memory device may also be provided for storing the transformer test sequence.
According to further aspects of the invention, a test sequence editor allows customization of the transformer test sequence.
Another embodiment of the present invention is directed to a method for testing a transformer comprising connecting the transformer to a processor comprising a transformer test engine; loading a customized transformer test sequence into the processor; and executing the customized transformer test sequence with the transformer test engine.
According to aspects of the invention, results of the execution are provided to the processor along with transformer specifications to the processor. It is determined whether the transformer passes responsive to the results and the transformer specifications.
A further embodiment of the present invention is directed to a method for creating or editing a customized transformer test program comprising selecting at least one test instruction or pre-existing sequence of test instructions from a plurality of transformer test instructions; providing at least one associated parameter for each of the selected test instructions or pre-existing sequence of test instructions; and defining an order of execution of each of the test instructions.
According to aspects, of the invention, the order of execution of each of the test instructions is stored, and the test instructions are executed in accordance with the order. A transformer test sequence is generated based on the order.